The invention provides a preparation method of a nano-silver-containing 
sodium alginate based antibacterial medical dressing, and relates to an antibacterial medical dressing with 
sodium alginate as a main 
raw material, solving the problems that the air permeability is poor, the wettability is low, the antibacterial performance is not realized and the like in the existing dressing and a preparation method thereof. The medical dressing provided by the invention is composed of silver nanoparticles, 
sodium alginate and an 
interpenetrating polymer network film. The preparation method provided by the invention comprises the following steps: I, preparing nano-silver loaded 
sol; II, preparing a 
sodium alginate solution loaded with silver nanoparticles; III, preparing a crosslinked 
polymer solution; IV, preparing a mixing solution used for 
processing the dressing; V, preliminarily 
processing and forming the dressing; and VI, preparing the nano-silver-containing 
sodium alginate based antibacterial medical dressing. The dressing is able to quickly control major bleeding, has antibacterial performance, is outstanding in 
moisture absorption performance, high in 
moisture-vapor transmission and 
biocompatibility, and biodegradable, has the capacity of promoting 
wound healing and is low in price, simple and convenient to operate, and suitable for 
mass production.